blade sterilization ruining ht?

[Muaddib1116]

I've been watching a little Man, Woman, Wild. This thread isn't really about the merits of the show so much, but I noticed that they generally sterilize their knives in the fire prior to food prep, which makes sense. But it got me wondering if that could just destroy the HT of the blade, and the next time the guy tries to chop down a sapling or baton a log if the blade might not just crack. What type of temperatures and duration would be required to ruin a blades HT?

 

[goodeyesniper]

I've been watching a little Man, Woman, Wild. This thread isn't really about the merits of the show so much, but I noticed that they generally sterilize their knives in the fire prior to food prep, which makes sense. But it got me wondering if that could just destroy the HT of the blade, and the next time the guy tries to chop down a sapling or baton a log if the blade might not just crack. What type of temperatures and duration would be required to ruin a blades HT?

i'm far from an expert, but I doubt you'd have to worry about it.

for tempering it's usually several hundred degrees for an hour or more cook time. For HT it's getting the steel up around the point where it glows red hot, or hotter.... putting it at the top of a flame for a matter of seconds shouldn't do much....

 

[Tsujigiri]

Yeah, you'd need to get much hotter to change the heat treat. And if you did heat up the blade that much, I doubt it would cause the blade to crack. Heat treats soften the steel by annealing out some of the hard austenite phase, so the blade won't be so brittle it will crack and chip.

 

[Ryan M]

Haven't watched it, so I don't know if what they're doing would ruin the heat treat. But the general rule is, if carbon blacking appears on the blade, it was hot enough and/or long enough to damage the temper. I may know of someone who, when he was 12, turned some 440A into something resembling the hardness of butter, by trying to blacken the blade and make it all tacticool, by using fire to coat it in carbon black.

Any blacking is also likely to be a rather nasty contaminant. Random carbon isn't the same as activated charcoal at all. Wood fires naturally produce a small amount of buckytubes, which are essentially fiberglass bits from hell, if you inhale them, and are the component that does most of the lung damage associated with smoke inhalation, IIRC. I can't imagine eating fiberglass from hell being very good for the ol' intestines.

It'd be much smarter to boil the knives, as long as they aren't touching anything hotter than the water (bottom of a pot, hot rocks if using those, etc.). Boiling water is nowhere near hot enough to damage any temper, and boiling is probably one of the better cooking methods in a survival type thing anyway.

 

[A.P.F.]

Flame sterilization only takes moments. It is not the heating of the blade that kills the bacteria and virus contamination, it is the searing of the flame that nukes them.